The two suspects appeared in federal court in Seattle Thursday in tan prison garb and listened as prosecutor recited the charges against them. Detention hearings were set for Wednesday.

Their court-appointed defense lawyers declined to comment. The suspects could face life in prison if convicted.

Federal officials say the plot was uncovered when the suspects contacted a third man, who alerted Seattle police on June 3. The third man agreed to work with law enforcement and told the men he would help them get machine guns to attack the recruiting station on East Marginal Way south of downtown Seattle.

Investigators say the two had met the third man while serving time in prison.

After the police were tipped off, they put the men under intensive surveillance. The FBI monitored them on audio and videotape, discussing a violent assault on the military processing station.

The men originally planned to attack on Joint Base Lewis-McChord, a combined Army-Air Force base south of Tacoma, Wash., with machine guns and grenades, the federal complaint said.

According to the FBI, Abdul-Latif was angry about the United States military presence in Iraq and Afghanistan, and even in Yemen. Charging documents said Abdul-Latif believed "murdering American soldiers was justifiable."

FBI officials said Abdul-Latif "wanted to die as a martyr in the attack."

But after further Internet resesarch, the complaint said, the men decided on the recruit station as a target because it was a place where people who "wanted to go to Iraq and Afghanistan" would be, and most of the people there would be unarmed.

"It's a confined space, not a lot of people carrying weapons, and we'd have an advantage," Abdul-Latif allegedly said in a recording.

The federal complaint said that in the recordings, the suspects in the Seattle case discussed how to time their attack, such as by tossing grenades in the cafeteria.

"The key thing to remember here is, is we are not targeting anybody innocent — that means old people, women out of uniform, any children," Abdul-Latif is quoted as saying. "Just people who wear the green for the kaffir Army, that's who we're going after."

The FBI said Abdul-Latif and the informant went to the recruiting center on June 8 and looked around the property. Peering inside the front doors, Abdul-Latif noted a security guard inside, but allegedly said, "We'll just kill him right away ... we can kill him first."

On the same day, the informant was instructed by Abdul-Latif to get machine guns, ammunition and grenades to use during the attack, charging papers show.

Mujahidh came to Seattle from Los Angeles by bus on Monday, the FBI said.

The two bought what they thought were working machine guns, which turned out to have been rendered inoperable by the FBI. They were arrested late Wednesday night.

The Justice Department said Abdul-Latif and Mujahidh were charged by complaint with conspiracy to murder officers and employees of the United States, conspiracy to use a weapon of mass destruction (grenades), and possession of firearms in furtherance of crimes of violence. Abdul-Latif also was charged with two counts of illegal possession of firearms.

The Homeland Security Department said in a May 31 assessment with other organizations that it did not think it likely there would be coordinated terrorist attacks against military recruiting and National Guard facilities, The Associated Press reported.

But the agencies agreed that lone offenders or groups would continue to try to launch attacks against such facilities.